Accessibility evaluations of feeder transit services

Abstract

Transit systems play a vital role in the economic development of a region by providing commuters access to industry hubs and centers. The first/last mile transport connectivity to/from a major transit line further extends the opportunities of access to an increased number of industrial hubs and places of interest to an increased number of commuters from a remote community. This paper analyses the accessibility impacts for first/last mile transport connectivity to/from the major transit line using two most common feeder transit services – fixed route transit (FRT) and demand responsive transit (DRT). Analytical results show that for impedance decay factor (β) values equal to 1, the potential accessibility is a monotonically increasing function with respect to number of fixed stops visited by the FRT shuttle and number of passenger demands served by the DRT. The value of β greater than 1 results in maximizing the potential accessibility at an optimal number of fixed stops for FRT and an optimal number of passenger demand being served in a cycle for DRT. However, with a fractional value for β, there is no maximum or minimum potential accessibility that can be obtained either for the FRT or the DRT. Further, we illustrate the effects of impedance decay factor on accessibility using sensitivity analysis for the FRT and using simulations with real feeder like services operating in Denver, Colorado for the DRT. The handy formulas and equations developed in this paper can be extremely useful to transit planners and policy-makers in quickly deciding on an optimal feeder service operating policy for maximizing accessibility to/from a major transit line stop.